Sample viscosity can be a source of analytical error when discrete sampler-dilutors are used.
Total protein concentration in the serum of a patient with hyperviscosity syndrome differed as measured by the biuret procedure in the DuPont aca (80 g/L) and the SMA 12/60 (105 g/L), owing to viscosity-dependent errors with the aca sampling system; the magnitude depended on sample temperature and volume of sample aspirated. This kind of error was not observed with the SMA 12/60 and was far less severe when a Micromedic sampler-dilutor was tested. It could be eliminated in the case of the aca by adding sample to test packs with a syringe rather than with the aca automated sampler-dilutor. We thus recommend use of the syringe method when unusually viscous samples (serum or other body fluids) are analyzed in the aca.
D001322:Autoanalysis; D001798:Blood Proteins / Q000032:analysis*; D001809:Blood Viscosity; D003951:Diagnostic Errors; D005990:Glycerol; D006801:Humans; D013696:Temperature; D008258:Waldenstrom Macroglobulinemia / Q000097:blood*
D001798:Blood Proteins; D005990:Glycerol